Farfisa spinet model 112452 help needed

[farace]

I'm new here, and I'm not an organ person per se (I'm a bassist), though I do have a cool old Crumar T-1 and an Optigan. I'm here seeking help for a Farfisa spinet style model 112452 organ that my partner picked up the other day. She's excited about it, but we have a problem. All the C notes are much too sharp, way out of the range of adjustment. (All the other notes were flat about 5 cents plus or minus, and I tuned them up without problem. It sounds great, except for those pesky Cs. When I first started on it, they were sounding about halfway between E and F; now they're closer to between Db and D. It seems to drift an awful lot, though.

Searching for information specific to this model has been fruitless so far, and the oscillator boards don't quite resemble the examples I've found online for other Farfisas. This organ has two oscillator circuit boards with six notes each.

It seems that someone in the past has had trouble with tuning the C as well, because there is a capacitor tack-soldered onto the circuit. It appears to be 430 pF.

I have watched the "tuning a Farfisa" video from Vintage Vibe, but it doesn't really answer anything. In fact, it raises other questions for me: 1) should the original repair made to this organ have used two capacitors rather than one? 2) is there no more precise way to determine the correct value than trial and error?

The other thing nagging at me is the drifting--could I be chasing the wrong problem?

We're grateful for any help anyone can offer. Thanks!

--Bob

P.S. I took a couple of photos of the board and tacked-on capacitor, but I don't see a way to include them in the post.

[farace]

Another detail that maybe I should have mentioned is that this organ has trim pots for tuning and not the coil/ferrite core arrangement I've seen in my searching around. I also took a closer look at where the capacitor is tack-soldered in place, and it appears that one end is tacked to one leg of one oscillator and the other end is tacked to a leg of the other oscillator. The transistors are all BC208B and there are three of them per note section.

--Bob

[farace]

Apparently I can now attach images. Here are photos of both sides of the board in the area of the out-of-tune C.

Failing suggestions, I'm going to take a measured shotgun approach. I am awaiting delivery of replacements for the two 1560 pF caps that have the added cap tacked across them.

[andyg]

Can we have a photo of the organ please, as I don't recognise that model number. That looks more like a serial number.

Depending on how old the organ is, and it could be anywhere from the 60s to the 80s, you might think about checking what sort of voltages are coming out from the power supply, though without a service manual I suppose you wouldn't know what they were suppose to be. But it would show if anything's ridiculously low. Think about recapping the power supply if it's an oldie.

Do also remember that Farfisa spinet organs are pretty low quality for the most part - that extra cap might even have been a factory mod to fix a problem that cropped up after the boards had been produced.

[farace]

Because of where it is positioned right now, I can't take a good photo, but I found this image online of a Farfisa that seems identical, including the rhythm machine to the right of the lower manual, and the cassette deck to the left. Not clear from the photo is that it has a roll top cover. There is reverb, vibrato, and a two-speed Leslie built in. Footages run 4', 8', and 16' with no fractional footages.

The model number is definitely 112452; it's stamped on the ID plate as the model, and there is a separate serial number below it.

I do plan to recap the power supply, and it's a little noisy, but I want to get the C notes in tune first (the others are still fine). I'm hoping against hope that the original caps have drifted so much that replacing them will bring that section back in spec. It doesn't cost much to try it, just waiting for them to arrive.

[farace]

FWIW, I found a manual on eBay showing and giving specs for several Farfisa "Partner" models. The one listed on the back as model 52RKL seems to be identical to this, though I can't find that model designation on it anywhere.

i got the replacement caps in today, and at first it didn't seem to help. After letting it warm up for an hour, the Cs came in tune. Not sure what to think of that, but we'll see how it acts in the next few days.

[farace]

Scratch that--the in-tune Cs were an anomaly. :(

[tucsondave]

I found a Farfisa model cross reference list. The 112452 (control number) does indeed cross to a model # 52 with a possible suffix of R, K, or RK.

td

[Thud]

Hi, I know this is an old thread but just on the off chance, are you still in there Tucsondave? I'm interested in the Farfisa cross-reference list you mentioned. Could I obtain a copy too? Also, if the OP is still around, how did you get on with your tuning problems?

Cheers

[farace]

Hi, I know this is an old thread but just on the off chance, are you still in there Tucsondave? I'm interested in the Farfisa cross-reference list you mentioned. Could I obtain a copy too? Also, if the OP is still around, how did you get on with your tuning problems?

Cheers

I had to button it up, telling myself I'd get back to it. Hasn't happened yet, and other projects have taken priority. I've also gotten to where space is at a premium, and I've been considering letting someone take the organ off my hands, if they promise not to scrap it.